A reclosable bag that is a bag openable and closable by belt-like zipper members (an engaging unit) of a male and a female, the zipper members provided to an opening/closing portion of the bag, has been used for many fields such as food, medical products and miscellaneous goods.
In manufacturing such a bag with the zipper members, a method has been known in which the zipper members are formed by extrusion molding while being welded to a surface of the bag film. However, the method contains a limitation on flexibility in combination of the zipper members and the bag film since the zipper members are welded at the same time as the molding. In addition, the molding of the zipper members cannot be conducted independently and the molding needs to be conducted with a limitation in cooling. Hence, it has been difficult to stably manufacture the bag with the zipper members.
As one example of related art technique for manufacturing the bag with the zipper members, there has been known an arrangement in which bag films are overlaid with each other while sandwiching tapes with the male and female zipper members in engagement, flat-plate-like seal bars are provided on outer sides of the bag films such that the seal bars can advance to and retract from the bag films, the bag films and the tapes with the zipper members are intermittently sent at a constant length pitch and the seal bars are brought into contact with the bag films, so that the tapes with the zipper members are welded to the bag films by utilizing heat of the seal bars (Patent Document 1). In Patent Document 1, a separator is disposed between the facing tapes with the zipper members.
As another example of the related art, there has been known an arrangement in which, when the tapes with the zipper members are welded to the bag films, the tapes and the bag films are continuously moved by rotation of the rotary drum while the tapes and the bag films are overlaid with each other such that the zipper members travel in a zipper member introducing groove formed along a circumferential direction of the rotary drum (Patent Document). In Patent Document 2, the zipper member introducing groove is formed in a rectangular shape. In the zipper member introducing groove, the zipper member is accommodated. A tape portion integrally provided to the zipper member has a larger width dimension to be welded to the bag film, the tape portion disposed along an outer circumferential surface of the rotary drum such that the tape portion can be welded to the bag film.
[Patent Document 1] JP-UM-B-H03-36825 (FIGS. 2 and 3)
[Patent Document 2] JP-A-H09-39121 (FIGS. 2 and 3)